[原文]The Lanap BotDetect APS.NET CAPTCHA component before 1.5.4.0 stores the UUID and hash for a CAPTCHA in the ViewState of a page, which makes it easier for remote attackers to conduct automated attacks by "replaying the ViewState for a known number."

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漏洞信息 (F47765)

Symantec Vulnerability Research Security Advisory SYMSA-2006-005 - The CAPTCHA component for ASP.NET provided by Lanap may be completely bypassed, thus undermining the security benefit of the CAPTCHA technology.

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Symantec Vulnerability Research
http://www.symantec.com/research
Security Advisory
Advisory ID : SYMSA-2006-005
Advisory Title: Lanap CAPTCHA bypass exposure
Author : Michael White, michael_white@symantec.com and
Graham Murphy, graham_murphy@symantec.com
Release Date : 23-06-2006
Application : BotDetect Lanap CAPTCHA component
Platform : ASP.NET
Severity : Low/Limited exposure
Vendor status : Vendor verified, patch available
CVE Number : CVE-2006-2918
Reference : http://www.securityfocus.com/bid/18315
Overview:
The CAPTCHA component for ASP.NET provided by Lanap may be
completely bypassed, thus undermining the security benefit
of the CAPTCHA technology.
Details:
During a consulting engagement, Symantec identified that the
Lanap CAPTCHA component stores the UUID and hash for a given
CAPTCHA within the page ViewState. By replaying the ViewState
for a known number, a remote attacker may avoid the CAPTCHA
entirely.
This behaviour is dependent on the way in which the Lanap
component is integrated, however numerous examples including
Lanap's demo code are identified as exhibiting this behaviour.
Vendor Response:
The above vulnerability has been fixed in the latest release
of the product, BotDetect ASP.NET CAPTCHA 1.5.4.0.
Licensed and evaluation versions of Lanap BotDetect ASP.NET
CAPTCHA are available for customer download from the Lanap
website at http://www.lanapsoft.com
If there are any further questions about this statement, please
contact Lanap support.
Recommendation:
Upgrade to the latest release of the product,
BotDetect ASP.NET CAPTCHA 1.5.4.0.
Common Vulnerabilities and Exposures (CVE) Information:
The Common Vulnerabilities and Exposures (CVE) project has assigned
the following names to these issues. These are candidates for
inclusion in the CVE list (http://cve.mitre.org), which standardizes
names for security problems.
CVE-2006-2918
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